ActorFlow.askWithContext

Use the “Ask Pattern” to send each stream element (without the context) as an ask to the target actor (of the new actors API), and expect a reply of Type StatusReply[T]StatusReply<T> where the T will be unwrapped and emitted downstream.

Actor interop operators

Dependency

This operator is included in:

sbt

val PekkoVersion = "1.1.2+29-e21fa9eb-SNAPSHOT"
libraryDependencies += "org.apache.pekko" %% "pekko-stream-typed" % PekkoVersion

Maven

<properties>
  <scala.binary.version>2.13</scala.binary.version>
</properties>
<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>org.apache.pekko</groupId>
      <artifactId>pekko-bom_${scala.binary.version}</artifactId>
      <version>1.1.2+29-e21fa9eb-SNAPSHOT</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>
<dependencies>
  <dependency>
    <groupId>org.apache.pekko</groupId>
    <artifactId>pekko-stream-typed_${scala.binary.version}</artifactId>
  </dependency>
</dependencies>

Gradle

def versions = [
  ScalaBinary: "2.13"
]
dependencies {
  implementation platform("org.apache.pekko:pekko-bom_${versions.ScalaBinary}:1.1.2+29-e21fa9eb-SNAPSHOT")

  implementation "org.apache.pekko:pekko-stream-typed_${versions.ScalaBinary}"
}

Signature

ActorFlow.askWithStatusAndContextActorFlow.askWithStatusAndContext { scala=“#askWithStatusAndContextI,Q,A,Ctx(ref:org.apache.pekko.actor.typed.ActorRef[Q])(makeMessage:(I,org.apache.pekko.actor.typed.ActorRef[org.apache.pekko.pattern.StatusReply[A]])=>Q)(implicittimeout:org.apache.pekko.util.Timeout):org.apache.pekko.stream.scaladsl.Flow[(I,Ctx),(A,Ctx),org.apache.pekko.NotUsed]” java =“#askWithStatusAndContextI,Q,A,Ctx” }

Description

Use the Ask pattern to send a request-reply message to the target ref actor when you expect the reply to be org.apache.pekko.pattern.StatusReply. The stream context is not sent, instead it is locally recombined to the actor’s reply.

If any of the asks times out it will fail the stream with an AskTimeoutExceptionAskTimeoutException.

The ask operator requires

• the actor ref,
• a makeMessage function to create the message sent to the actor from the incoming element, and the actor ref accepting the actor’s reply message
• a timeout.

Reactive Streams semantics